As per https://git.savannah.gnu.org/gitweb/?p=gperf.git;a=blob;f=COPYING;h=94a9ed024d3859793618152ea559a168bbcbb5e2;hb=165bba235b2e3289967e505411500e08151f63e9 and e.g. https://git.savannah.gnu.org/gitweb/?p=gperf.git;a=blob;f=src/bool-array.cc;h=d0e3364fe6946b824f6ebad1a55b8e6d1fe13b3c;hb=165bba235b2e3289967e505411500e08151f63e9 LICENSE should be GPL-3+ According to https://git.savannah.gnu.org/gitweb/?p=gperf.git;a=blob;f=ChangeLog;h=d1926b7bd67f116c80d02d182983698715766834;hb=165bba235b2e3289967e505411500e08151f63e9 switch was in 2008. Reproducible: Always